JPS6337498B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to improve the printed circuit board and the wire bonding method in a semiconductor device in which semiconductor pellets are directly mounted on the printed circuit board.

Among semiconductor devices, those in which semiconductor pellets are directly mounted on a printed circuit board (referred to as a printed circuit board, PCB) have the advantage that the entire semiconductor device can be made small and thin, and are therefore used in small devices such as wristwatches. It will be done. This type of semiconductor device includes leads etc. using copper foil on the front and back surfaces of a glass epoxy substrate 1 formed into a predetermined shape, as shown in FIGS. 1 and 2 for example for wristwatches. Form circuit 2,
On the other hand, a semiconductor pellet 3 is fixed to a part of this glass epoxy substrate 1, and a wire 5 is bonded between the electrode pad 4 of this pellet 3 and the circuit (lead) 2, and then the pellet 3 and wire 5 are bonded with resin. It is designed to be sealed with a mold.

By the way, in recent years, when wire bonding is performed between the electrode pad 4 and the lead 2, the bonding is automatically performed. That is, since the electrode pads formed on the pellet 3 and the leads formed on the printed circuit board 1 are formed using photographic technology, their positions on the pellet and printed circuit board 1 are constant. This is because it is suitable for automation.

However, since the semiconductor pellet 3 is not necessarily fixed on the printed circuit board 1 in a fixed position, an error in the relative position between the two may cause a deviation in the relative position between the electrode pad and the lead. become. For this reason, conventionally, the positions of the electrode pads 4 and leads 2 are detected and stored by a computer before bonding, and automatic bonding is performed based on this data. In this case, when detecting the position of the electrode pads, each pad is formed into a minute size and can be recognized as a point, so it is necessary to select two or more arbitrary pads from among each pad and detect their position. The entire pellet can be located,
From now on, all pad positions can be detected relatively easily and automatically. However, when detecting the position on the lead side, the width and length of each lead are made relatively large considering the working width of the wire bonding, so it is difficult to recognize this as a point. , therefore the lead position cannot be detected automatically.

For this reason, when determining the lead position, or in other words, the position of the printed circuit board, workers are forced to visually determine the position using a TV camera, etc., which is an obstacle to fully automating wire bonding. is the reality.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a printed circuit board for a semiconductor device that can perform wire bonding fully automatically, and a wire bonding method using this printed circuit board.

The gist of the present invention is to provide a semiconductor pellet having an electrode pad and a rectangular planar shape, a base (for example, a printed circuit board) for fixing the semiconductor pellet, and a wire bonding portion (for example, a printed circuit board) provided on the base. For example, in a semiconductor device having a wire bonding portion (the leading end of a lead) and wire bonding between the semiconductor pellet and the wire bonding portion, the wire bonding portion may be located near a first corner of the semiconductor pellet fixed to the base. a first position recognition pad that is optically recognizable on the base, and a second position recognition pad that is optically recognizable on the base and is located near a second corner of the semiconductor pellet. A semiconductor device is provided.

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 is a plan view of essential parts of the printed circuit board of the present invention, and FIG. 4 is a sectional view thereof. The printed circuit board 10 is mainly made of a glass epoxy board, and a predetermined circuit 12 is formed using copper foil on the front and back sides of this board.
is formed. A recess 11 is formed in a part of the surface of the printed circuit board 10 in the thickness direction, and a semiconductor pellet 13 is adhered into the recess 11 with silver paste 16 or the like. Around this recess 11, leads 12a for connecting wires 15 to a plurality of electrode pads 14 formed on the semiconductor pellet 13 are disposed in the circumferential direction, and are integrally formed with the circuit 12 in copper foil. It is formed by and,
In the present invention, microscopic rectangular position recognition pads 17 are formed at at least two locations near the lead 12a, three locations in this example. This pad 17 can be integrally formed of copper foil as a part of the lead or circuit when the lead 12a or circuit 12 is formed. The size of the pad 17 is preferably such that the position of the pad 17 can be recognized as a point, and in this embodiment, the size is set to 0.1 to 0.5 mm square. In the figure, 18 is a battery electrode formed on the back surface of the printed circuit board.

Next, a wire bonding method using the printed circuit board configured as described above will be explained.

When the semiconductor pellet 13 is fixed in the recess 11 of the printed circuit board 10, the position detection device 21, which is a combination of a TV camera 19 and a computer 20, is activated, as shown in FIG. This device 2
1 is an electrode pad 14 of a semiconductor pellet 13;
Two or more electrode pads 14a each selected from among the position recognition pads 17 of the printed circuit board 10
(Fig. 3) and the position of the position recognition pad 17, and when the position of each of these pads 14a, 17 is detected, the semiconductor pellet 1 is detected.
3 and the printed circuit board 10 can be detected. After detecting the relative positional relationship between the two, all the leads and electrode pads are calculated based on the patterns of the leads 12a and electrode pads 14 that have been stored in the computer in advance. The automatic wire bonder 22 can be activated by recognizing the position.

That is, by using the position recognition pads 17 formed on the printed circuit board 10, the position of the printed circuit board 10, in other words, the leads can be determined in exactly the same way as the position of the electrode pad 14 of the semiconductor pellet is automatically recognized. 12a can be automatically recognized. Therefore, there is no need for an operator to visually align the printed circuit board at the beginning of bonding, making it possible to fully automate bonding.

As described above, the semiconductor printed circuit board of the present invention has position recognition pads formed on at least two locations on its surface, while the wire bonding method of the present invention uses these position recognition pads to identify lead positions. Since the lead position can be detected and recognized in exactly the same way as the position of the electrode pad of a semiconductor pellet, the initial positioning work of the automatic wire bonding process can be performed automatically. This has the great effect of realizing fully automatic wire bonding.

According to the present invention, the relative positional relationship between the semiconductor pellet and the base can be recognized automatically and quickly with high precision, so that wire bonding between the pellet and the base can be automated.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a semiconductor pellet mounted on a printed circuit board, Fig. 2 is an enlarged plan view of the main part thereof, and Fig. 3 is an enlarged view of the main part of the present invention.
4 is a sectional view thereof, and FIG. 5 is a side view showing a position detection method. 10...Printed circuit board, 11...Recess, 12...
circuit, 12a... lead, 13... semiconductor pellet,
14, 14a... Electrode pad, 15... Wire, 17
...Position recognition pad, 19...TV camera, 20...Computer, 21...Position detection device, 22...Automatic wire bonder.

Claims (1)

[Scope of Claims] 1. A semiconductor pellet having an electrode pad and having a rectangular planar shape, a base for fixing the semiconductor pellet, and a wire bonding part provided on the base, In a semiconductor device in which wire bonding is performed between the semiconductor pellet and the wire bonding portion, there is a first optically recognizable first corner on the base near the first corner of the semiconductor pellet fixed to the base. 1. A semiconductor device comprising: a position recognition pad, the second position recognition pad being provided near a second corner of the semiconductor pellet and being optically recognizable on the base. 2. Claim 1, wherein the second corner is a corner opposite to the first corner.
1. Semiconductor device described in Section 1.